不同助剂对CuO-ZnO/SBA-15催化CO_2加氢制甲醇性能影响的研究

以硅质骨架结构介孔分子筛SBA-15为载体,采用浸渍法合成CuO-ZnO/SBA-15(CZ/SBA-15)、CuO-ZnO-MnO_2/SBA-15(CZM/SBA-15)、CuO-ZnO-ZrO_2/SBA-15(CZZ/SBA-15)三组多孔催化剂,在固定床反应器上评价了各组催化剂催化CO_2加氢合成甲醇的性能,同时结合N_2吸附-脱附(BET)、X射线衍射(XRD)、H_2程序升温还原(H_2-TPR)、程序升温脱附(H_2-TPD、CO_2-TPD)、N_2O滴定、X射线光电子能谱(XPS)、透射电子显微镜(TEM)等表征研究了不同助剂对CO_2催化加氢制甲醇的影响。结果表明,催化剂中的金属氧化物改变了SBA-15分子筛载体的孔径大小和比表面积;催化剂CuO-ZnO-MnO_2/SBA-15、CuO-Zn O-ZrO_2/SBA-15中铜的分散度(D_(Cu))和比表面积(A_(Cu))更大,表面CuO粒径更小,更易被还原;相比Mn-O簇,Zr-O簇为增强了碱性位点,提高了甲醇选择性。此外,CuO-ZnO-ZrO_2/SBA-15具有更高的氧空位浓度,催化活性更好,其甲醇选择性为25.02%,与CuO-ZnO/SBA-15、CuO-ZnO-Mn O_2/SBA-15相比分别提高了28%和136.9%,催化效果最好。     

气相色谱法测定海洋沉积物中十氯酮残留

研究了提取溶剂效率、毛细管柱极性、净化条件及共溶出干扰物等因素对十氯酮测定的影响;对比了加速溶剂提取及超声波提取方式,考察了DB-17、DB-1701与DB-5毛细管柱分离度,及不同比例甲醇/正己烷混合溶液作为定容溶液的分析结果。建立了加速溶剂萃取,H2SO4净化分离,DB-5毛细管柱电子捕获检测器(ECD)-气相色谱法(GC)测定海洋沉积物介质中有机氯农药类持久性有机污染物十氯酮残留分析方法。将5 g沉积物干样与3 g活化铜粉及3 g无水Na2SO4混匀后,采用二氯甲烷-丙酮(1∶1,V/V)进行加速溶剂萃取;萃取液浓缩后,用H2SO4净化,以1%甲醇-正己烷混合溶液定容后,采用DB-5非极性毛细管柱,及配备电子捕获检测器气相色谱测定十氯酮含量。本方法采用外标法进行定量分析,在0.005～0.1 mg/L浓度范围内,线性相关系数为0.9989;加标回收率为75%～98%;相对标准偏差为3.7%～9.6%(n=6);检出限为0.12 ng/g。     

氩氧流量比对CeOx-SnOx膜微观结构及光学性能的影响

采用磁控反应共溅射的方法,以金属Ce和Sn为金属源,成功地制备出CeOx-SnOx薄膜.利用扫描电子显微镜(SEM)、X射线衍射(XRD)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)等测试手段对薄膜的结构、表面形貌及成分进行了分析和表征.结果表明薄膜以岛状模式生长,随氩氧比降低,结晶性增强,出现CeO2和SnO相.此外,利用紫外-可见分光光度计对薄膜的光学性能进行了研究,测试结果表明薄膜对紫外光有极强的吸收作用.当氩氧流量比为3∶1时,紫外光平均透过率仅为5.80;,而可见光平均透过率为81.48;.     

光学实验教学法的改进

对光学实验教学法做了一些改进：1)将单个光学实验划分为相对独立的单元，每个单元用不同的实验方法研究一个待测的物理量或观察分析一个物理现象；2)加强预习报告要求；3)以调整仪器为主的操作考核。     

The Other Side of the Network Coin: Cost Considerations of Network Structure

The purpose of this study is to investigate the differential impact that inter-organizational network connections have on organizational level change. Drawing from the strategic leaning perspective on adaptation, this study investigates how the nature of inter-organizational ties among top management impact the cost and the effectiveness of an organizational level change process. To build on the existing empirical work in this area, this study employs a virtual experiment to create a controlled laboratory investigation of the hypothesized relationships among the strength, formalization, and functional equivalence of network ties; and the cost and effectiveness of an organizational change process. The findings of this study provide support for the strength of weak ties argument and structural hole theory, in addition to suggesting a caveat to Galbraith's information processing model. Furthermore, the results reveal that the tradeoff between increasing effectiveness and decreasing costs is not universally applicable across all decisions regarding network structure.     

Two-amplitude model of pion DCX applied to the 18O angular distribution and excitation function

An earlier model developed to fit the DCX excitation function of ¹⁸O has been extended to account for the $\text{T}{}_{\mathrm{\pi }}\text{= 164}\text{MeV}{}^{18}\text{O DCX}$ angular distribution in terms of that for ¹⁶O and a double-isobaric-analog transition.